Dislocation of crystalline or artificial intraocular lens (IOL) is a known complication of phacoemulsification and blunt trauma.[1],[2] This may lead to elevated intraocular pressure (IOP), corneal edema, uveitis, cystoid macular edema (CME), or retinal detachment (RD) resulting in profound visual loss.[3],[4],[5] Various studies support pars plana vitrectomy (PPV) for favorable visual outcome in such cases.[4],[6],[7] However, the associated postoperative complications may be raised IOP, RD, corneal decompensation, and CME.[8] The aim of our study was to evaluate the pre- and post-operative factors determining the visual outcome in patients undergoing PPV for dislocated lens.

Subjects and Methods

The study was performed in accordance with the ethical standards of the Institutional Committee on human experimentation and with the Helsinki Declaration of 1975 as revised in 2000.

A retrospective review was performed of the records of all patients who underwent PPV and retrieval of dislocated crystalline lens/IOL during 3 years from August 2012 to July 2015. Patients having ocular conditions which independently affect the visual outcome (including irreversible corneal disorders, advanced proliferative vitreoretinopathies, macular degenerations, glaucoma, uveitis, or optic neuropathies) and patients with <6-month follow-up were excluded from the study.

The surgical technique consisted of making a 6–7 mm sclera-corneal tunnel, followed by standard 20-gauge three-port PPV, and complete removal of vitreous strands adherent to the dropped crystalline lens or IOL. The lens was brought into the anterior chamber using vacuum aspiration in cases of dropped crystalline lens and intravitreal forceps in cases of dropped IOL, which was then delivered out through the sclera-corneal tunnel. If there was more than 180° of capsular remnant, a three-piece posterior chamber IOL was placed in the sulcus, and if there was no capsular remnant, an anterior chamber IOL was implanted.

Fifty-eight eyes of 58 patients including 42 male and 16 female patients were studied. The surgery was performed for ten patients with dislocated nuclear fragment(s) due to cataract surgery, 26 patients with dislocated IOL due to cataract surgery, twenty patients with traumatic dislocation of crystalline lens, and two patients with traumatic dislocation of IOL. Out of the 36 patients who had iatrogenic dislocation related to cataract surgery, 26 patients (72.2%) underwent phacoemulsification, and ten patients (27.8%) underwent small-incision cataract surgery (SICS). The odds of phacoemulsification causing dislocation are 6.8 times higher as compared to SICS (P = 0.001). Out of the 22 cases of trauma, two (9.1%) patients had suffered penetrating trauma, and the rest of them sustained blunt trauma. The odds of blunt trauma causing dislocation are 100 times higher as compared to penetrating trauma (P = 0.001).

The distribution of the latency between dislocation and surgery of the patients is shown in [Table 1], and the distribution of the final visual outcomes at 6-month follow-up is shown in [Table 2].

Table 1: Distribution of time duration between dislocation and surgery (n=58)

Final BCVA of 6/60 or better was found in the majority of patients who underwent PPV within 1 year of dislocation, but for all patients who were delayed for over a year, the final BCVA was <6/60 (P = 0.001).

The preoperative complications were raised IOP in six (10.3%) patients, corneal edema in four (6.9%), uveitis in two (3.4%), and VH in four (6.9%) patients. Preoperative uveitis had a significant correlation with dislocated nuclear fragment(s) following cataract surgery (P = 0.007) when compared to iatrogenic dislocation of IOL and traumatic dislocation. In addition, the final BCVA had significant correlations with preoperative corneal edema (P = 0.001) and uveitis (P = 0.039). All patients with preoperative corneal edema and uveitis had final BCVA <6/60.

The postoperative complications seen in this study are raised IOP in twelve (20.7%), corneal decompensation in eight (13.8%), uveitis in eight (13.8%), CME in four (6.9%), RD in four (6.9%), and foveal thinning in two (3.4%) patients. The final BCVA had significant correlations with postoperative corneal decompensation (P = 0.013), CME (P = 0.001), and RD (P = 0.001). All patients with postoperative CME and RD had final BCVA <6/60, whereas 50% patients with postoperative corneal decompensation had final BCVA between 6/12 and 6/60, and the rest 50% had final BCVA <6/60 despite adequate treatment. Furthermore, RD was seen in patients whose PPV was delayed over a month, which was statistically significant (P = 0.001). CME had significant correlations with iatrogenic dislocation of nuclear fragment(s) (P = 0.001) and preoperative uveitis (P = 0.001). In addition, postoperative corneal decompensation had a significant correlation with preoperative corneal edema (P = 0.03).

Discussion

PPV for retrieval of dislocated crystalline lens or artificial IOL is a necessary intervention for visual rehabilitation and to prevent several sight-threatening complications.[3],[4],[5] However, there are certain factors that predict the visual outcome and future complications. Our study has shown that postoperative complications such as corneal decompensation, CME, and RD have resulted in poor visual outcomes with majority of the patients having BCVA <6/60. In our study, we managed to evaluate the risk factors for such sight-threatening complications. We found that patients having preoperative corneal edema are likely to develop corneal decompensation following the procedure due to endothelial injury. In our study, dislocated nuclear fragment(s) as a result of complicated cataract surgery increases the risk of CME. This can be supported by a previous study done by Jaffe et al.[10] and explainable as the presence of lens matter in vitreous is likely to induce uveitis. Excessive manipulation during the primary surgery (in this case, cataract surgery) may also induce uveitis which later increases the chances of CME. We have also found that delayed presentation and intervention are likely to result in a poor visual outcome due to increased risk of RD. This is in agreement with the previous studies that state that RD is a well-documented complication of lenticular dislocation if vitrectomy is delayed.[8],[11]

Conclusions

The risk factors for poor visual outcomes associated with the procedure should be assessed, explained to the patients, and kept on close watch in their postoperative follow-up visits.